The single file which represented the bulk of the `meteor self-test`
functionality had got a bit heavy and it stood to benefit from some
dissemination.
I embarked on this change originally when looking into replacing
PhantomJS with Chrome Headless (and a new `ChromeClient` class) within
self-test. Unfortunately, I didn't have time to take this the last
step of actually implementing Chrome, but this should hopefully
facilitate that change in the future by providing what I believe to be
better compartmentalization of this logic.
I apologize for the (likely) difficulty of reviewing this commit. Due
to heavy intertwining of existing code it was hard to arrange these
changes in an easy-to-review manner. I believe a reviewer will
find that it's mainly copy and pasting into different files and
careful adjusting of those files (new) module dependencies.
